Abstract:

Biogeochemical cycling of phosphate is a key component in the overall production rate
of coastal ecosystems. Mineral phases in the near-shore sediments play a significant role
in the return of phosphate remineralized in the upper sediments to the water column.
Sequential Extraction (SEDEX) of the solid-phase associated PO4-3 yielded reservoir
profiles of phosphate at three sites off of the Massachusetts coast. These extractions
found Fe-associated PO4 to be the dominant phase associated with rapid porewater-solid
P exchange. Additionally, a seasonal enrichment/depletion pattern of phosphate fluxes
relative to total carbon was observed from the sediments. These observations established
the behavior of phosphate in coastal sediments as interconnected with the ongoing Fe-cycling
in the sediments as well.

Description:

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2008.